The Occupational Studies Section conducts epidemiologic studies to identify and quantify occupational and other causes of cancer. During the past year investigations have uncovered associations between lymphatic and hematopoietic, skin, lip, brain, stomach, and prostate cancer and employment as a farmer. Use of several pesticides including carbaryl, diazinon, dichlorvos, and malathion was linked with non- Hodgkin's lymphoma. Lung cancer was excessive among silicotics previously employed in the dusty trades in North Carolina, but not among workers exposed to silica in China. Multiple myeloma and non-Hodgkin's lymphoma were elevated among workers at an Air Force base with potential exposure to various organic solvents. Risks were particularly high among women. Personal use of hair dyes appeared to increase the risk of non- Hodgkin's lymphoma and multiple myeloma among men and women from Nebraska. Risks were greater among those who used dark, permanent dyes. Associations between certain HLA genotypes and multiple myeloma points to a role for genetic factors into the origin of this tumor. Tobacco was associated with the development of colon polyps and leukemia, but not with multiple myeloma. Currently under investigation include studies of pesticides, benzene, methylene chloride, acrylonitrile, formaldehyde, benzidine asbestos, silica, and methodologic investigations to improve exposure assessments. Occupational groups with complex exposures under study include jewelry manufacturers, laboratory workers, farmers, industrial workers in Turkey, pesticide applicators, and embalmers.